Power strip is a mobile socket, also known as a plug board or a trailer board. It is an indispensable tool for people in their daily life and brings convenience to them. However, the power strips in our daily life in most of the cases are provided with exposed receptacles. In addition, the receptacle end face has to be exposed to the outside in use. As a result, a long time of use tends to lead to dust accumulation or other foreign substances falling into the receptacles, which may lead to electric shock accidents, as a human body touching a power strip with exposed receptacles would do under wet conditions.